Explanation: In the Summer of 1054 A.D.
Chinese astronomers reported
that a star in the
constellation of Taurus suddenly became as bright as the full Moon.
Fading slowly, it remained visible for over a year.
It is now understood
that a spectacular supernova explosion -
the detonation of a massive star whose remains
are now visible as the Crab Nebula-
was responsible for the apparition.
The
core of the star collapsed to form a rotating
neutron
star or
pulsar,
one of the most exotic objects known to modern astronomers.
Like a cosmic lighthouse, the rotating Crab pulsar generates beams of
radio, visible, x-ray and
gamma-ray energy which, as the name
suggests, produce pulses as they sweep across our view.
Using a stunning series of
visible
light images taken with
the Hubble Space Telescope (HST) in 1995, astronomers have discovered
spectacular pulsar powered motions within the Crab nebula.
Highlights of this
HST Crab "movie" show wisps of material moving
away from the pulsar at half the speed of light, a scintillating halo,
and an intense knot of emission dancing, sprite-like, above the pulsar's pole.
Only 10 kilometers wide but more
massive than the sun, the pulsar's energy drives the dynamics and emission
of the nebula itself which is more than 10 light-years across.